The Physical Strenuousness of Work is Slightly Associated with an Upward Trend in the Body Mass Index

This paper explores the relationship between the physical strenuousness of work and the body mass index in Finland, using individual microdata over the period 1972-2002. The data contain self-reported information about the physical strenuousness of a respondent’s current occupation. Our estimates show that the changes in the physical strenuousness of work can explain around 8% at most of the definite increase in BMI observed over the period. The main reason for this appears to be that the quantitative magnitude of the effect of the physical strenuousness of work on BMI is rather moderate. Hence, according to the point estimates, BMI is only around 1.5% lower when one’s current occupation is physically very demanding and involves lifting and carrying heavy objects compared with sedentary job (reference group of the estimations), other things being equal. Accordingly, the changes in eating habits and the amount of physical activity during leisure time must be the most important contributors to the upward trend in BMI in industrialised countries, but not the changes in the labour market structure.

Online association policies in IEEE 802.11 WLANs

In this paper, we study the performance of client-Access Point (AP) association policies in IEEE 802.11 based WLANs. In many scenarios, clients have a choice of APs with whom they can associate. We are interested in finding association policies which lead to optimal system performance. More specifically, we study the stability of different association policies as a function of the spatial distribution of arriving clients. We find for each policy the range of client arrival rates for which the system is stable. For small networks, we use Lyapunov function methods to formally establish the stability or instability of certain policies in specific scenarios. The RAT heuristic policy introduced in our prior work is shown to have very good stability properties when compared to several other natural policies. We also validate our analytical results by detailed simulation employing the IEEE 802.11 MAC.

Organisation Carescapes: Researching Organisations, Work and Care

This working paper develops an approach to the analysis of care as it is evident in the policies and practices of employing organisations. We identify how notions of care are incorporated in myriad and multi-faceted ways that may support, survey and control workers, as well as having implications for employers, managers, employees and workers. Aspects of care can be found in a range of statutory duties, policies and related activities, including: health and safety, equality and diversity, parental leave, religious observance, bullying and harassment, personal development, voluntary redundancy, early retirement, employer pension schemes, grievance procedures, and dismissal. The conceptual framework of organisation carescapes is offered as an aid to the analysis of employee policies and services. These policies and services are transformed by shifts in supranational and national policies such as European Union (EU) economic strategies and national legislation on disability rights legislation, age discrimination and flexible working, and changes in labour market competitiveness. In conclusion, we consider how the framework of organisation carescapes is informing research design in our and our colleagues’ ongoing programme of research.

Nonlinear intrinsic instability of solid propellant combustion including gas-phase thermal inertia

The problem of homogeneous solid propellant combustion instability is studied with a one-dimensional flame model, including the effects of gas-phase thermal inertia and nonlinearity. Computational results presented in this paper show nonlinear instabilities inherent in the equations, due to which periodic burning is found even under steady ambient conditions such as pressure. The stability boundary is obtained in terms of Denison-Baum parameters. It is found that inclusion of gas-phase thermal inertia stabilizes the combustion. Also, the effect of a distributed heat release in the gas phase, compared to the flame sheet model, is to destabilize the burning. Direct calculations for finite amplitude pressure disturbances show that two distinct resonant modes exist, the first one near the natural frequency as obtained from intrinsic instability analysis and a second mode occurring at a much higher driving frequency. It is found that er rn in the low frequency region, the response of the propellant is significantly affected by the specific type of gas-phase chemical heat-release model employed. Examination of frequency response function reveals that the role of gas-phase thermal inertia is to stabilize the burning near the first resonant mode. Calculations made for different amplitudes of driving pressure show that the mean burning rate decreases with increasing amplitude. Also, with an increase in the driving amplitude, higher harmonics are generated in the burning rate.

Adhesion-Induced Instability in Asperities

Adhesive forces between two approaching asperities will deform the asperities, and under certain conditions this will result in a sudden runaway deformations leading to a jump-to-contact instability. We present finite element-based numerical studies on adhesion-induced deformation and instability in asperities. We consider the adhesive force acting on an asperity, when it is brought near a rigid half-space, due to van der Waals interaction between the asperity and the half-space. The adhesive force is considered to be distributed over the volume of the asperity (body force), thus resulting in more realistic simulations for the length scales considered. Iteration scheme based on a ``residual stress update'' algorithm is used to capture the effect of deformation on the adhesion force, and thereby the equilibrium configuration and the corresponding force. The numerical results are compared with the previous approximate analytical solutions for adhesion force, deformation of the asperity and adhesion-induced mechanical instability (jump-to-contact). It is observed that the instability can occur at separations much higher,and could possibly explain the higher value of instability separation observed in experiments. The stresses in asperities, particularly in case of small ones, are found to be high enough to cause yielding before jump -to-contact. The effect of roughness is considered by modeling a spherical protrusion on the hemispherical asperity.This small-scale roughness at the tip of the asperities is found to control the deformation behavior at small separations, and hence are important in determining the friction and wear due to the jump-to-contact instability.

Social factors at work and the health of employees

Masennus, ahdistuneisuus, alkoholiriippuvuus ja alkoholin väärinkäyttö sekä unihäiriöt ovat yleisiä ongelmia työssä käyvän väestön keskuudessa. Nämä sairaudet ja oireet aiheuttavat huomattavia kuluja myös yhteiskunnalle. Sosiaalisen tuen ja työilmapiirin yhteyttä työssä käyvien (n = 3 347–3 430) terveyteen tutkittiin Terveyden ja hyvinvoinnin laitoksen Terveys 2000 -aineistossa. Sosiaalista tukea työssä mitattiin JCQ-kyselyllä (Job Content Questionnaire) ja yksityiselämän sosiaalista tukea SSQ-kyselyllä (Social Support Questionnaire). Työilmapiiriä mitattiin kyselyllä, joka on osa Terve työyhteisö -kyselyä. Mielenterveyshäiriöiden diagnoosit perustuivat CIDI-haastatteluun (Composite International Diagnostic Interview). Tiedot lääkärin määräämistä masennus- ja unilääkkeistä poimittiin Kelan lääkerekisteristä ja tiedot työkyvyttömyyseläkkeistä Eläketurvakeskuksen ja Kelan rekistereistä. Ilmapiirin kokemisessa ei ollut merkitsevää eroa sukupuolten välillä. Sen sijaan naiset kokivat saavansa sosiaalista tukea enemmän sekä työssä että yksityiselämässä. Vähäinen sosiaalinen tuki sekä työssä että yksityiselämässä oli yhteydessä masennukseen, ahdistuneisuushäiriöihin ja moniin uniongelmiin. Huono työilmapiiri oli yhteydessä sekä masennukseen että ahdistuneisuushäiriöihin. Vähäinen tuki sekä esimiehiltä että työtovereilta oli yhteydessä myöhempään masennuslääkkeiden käyttöön. Huono työilmapiiri ennusti myös masennuslääkkeiden käyttöä. Vähäinen sosiaalinen tuki esimieheltä näytti lisäävän työkyvyttömyyseläkkeen todennäköisyyttä. Työhyvinvointiin täytyy kiinnittää huomiota, koska vähäinen sosiaalinen tuki ja huono työilmapiiri ovat yhteydessä mielenterveysongelmiin ja lisäävät työkyvyn menettämisen riskiä. – Englanninkielinen julkaisu. Suomenkielinen yhteenveto s. 89–90.

Experimental investigation of the dependence of barrier height on metal work function for metal---SiO2---p---Si (MIS) Schottky-barrier diodes in the presence of inversion

The dependence of barrier height on the metal work function of metal-SiO2-p-Si Schottky barrier diodes was investigated and nonlinearity was found. This is explained by the theoretical model proposed recently by Chattopadhyay and Daw. The values of interface trap density and fixed charge density of the insulating layer of the diodes were calculated using this model and found to be appreciably different from those estimated by the usual method.

Karyotype instability in the ponerine ant genus Diacamma

The queenless ponerine ant Diacamma ceylonense and a population of Diacamma from the Nilgiri hills which we refer to as `nilgiri', exhibit interesting similarities as well as dissimilarities. Molecular phylogenetic study of these morphologically almost similar taxa has shown that D ceylonense is closely related to `nilgiri' and indicates that `nilgiri' is a recent diversion in the Diacamma phylogenetic tree. However, there is a striking behavioural difference in the way reproductive monopoly is maintained by the respective gamergates (mated egg laying workers), and there is evidence that they are genetically differentiated, suggesting a lack of gene flow To develop a better understanding of the mechanism involved in speciation of Diacamma, we have analysed karyotypes of D. ceylonense and `nilgiri' In both, we found surprising inter-individual and intra-individual karyotypic mosaicism. The observed numerical variability, both at intra-individual and inter-individual levels, does not appear to have hampered the sustainability of the chromosomal diversity in each population under study Since the related D. indicum, displays no such intra-individual or inter-Individual variability whatsoever under identical experimental conditions, these results are unlikely to he artifacts. Although no known mechanisms can account for the observed karyotypic variability of this nature, we believe that the present findings on the ants under study would provide opportunities for exciting new discoveries concerning the origin, maintenance and significance of intra-individual and inter-individual karyotypic mosaicism.

Reasonability and the Linguistic - Division of Labor in Institutional Work

We examine institutional work from a discursive perspective and argue that reasonability, the existence of acceptable justifying reasons for beliefs and practices, is a key part of legitimation. Drawing on philosophy of language, we maintain that institutional work takes place in the context of ‘space of reasons’ determined by widely held assumptions about what is reasonable and what is not. We argue that reasonability provides the main contextual constraint of institutional work, its major outcome, and a key trigger for actors to engage in it. We draw on Hilary Putnam’s concept ‘division of linguistic labor’ to highlight the specialized distribution of knowledge and authority in defining valid ways of reasoning. In this view, individuals use institutionalized vocabularies to reason about their choices and understand their context with limited understanding of how and why these structures have become what they are. We highlight the need to understand how professions and other actors establish and maintain the criteria of reasoning in various areas of expertise through discursive institutional work.

A sufficient criterion for Rayleigh-Taylor instability of incompressible viscous three-layer flow

Using normal mode analysis Rayleigh-Taylor instability is investigated for three-layer viscous stratified incompressible steady flow, when the top 3rd and bottom 1st layers extend up to infinity, the middle layer has a small thickness δ. The wave Reynolds number in the middle layer is assumed to be sufficiently small. A dispersion relation (a seventh degree polynomial in wave frequency ω) valid up to the order of the maximal value of all possible Kj (j less-than-or-equals, slant 0, K is the wave number) in each coefficient of the polynomial is obtained. A sufficient condition for instability is found out for the first time, pursuing a medium wavelength analysis. It depends on ratios (α and β) of the coefficients of viscosity, the thickness of the middle layer δ, surface tension ratio T and wave number K. This is a new analytical criterion for Rayleigh-Taylor instability of three-layer fluids. It recovers the results of the corresponding problem for two-layer fluids. Among the results obtained, it is observed that taking the coefficients of viscosity of 2nd and 3rd layers same can inhibit the effect of surface tension completely. For large wave number K, the thickness of the middle layer should be correspondingly small to keep the domain of dependence of the threshold wave number Kc constant for fixed α, β and T.

Therapeutic work with the present moment: A conversation analytical study of guidance into immediacy

Therapeutic work with the client’s present moment experience in existential therapy was studied by means of conversation analysis. Using publicly available video recordings of therapy sessions as data, an existential therapist’s practice of guiding a client into immediacy, or refocusing the talk on a client’s immediate experience, was described and compared with a therapist’s corresponding action in cognitive therapy. The study contributes to the description of interactional practice of existential therapy, and involves the first application of conversation analysis to a comparative study of psychotherapy process. The potential utility of this approach and the clinical and empirical implications of the present findings are discussed.